Feeler tip for weft detectors



June 30, 1936. 0. V; PAYNE 2,045,960

FEELER TIP FOR WEF'I DETECTORS Filed June 21, 1934 snoenfior Gscur LlPe ne fwr 1.

cltt orneqa Patented June 30, 1936 UNITED STATES PATENT oFFicE FEELER TIP FOR WEFT DETECTORS .Applicationnlune 21, 19.34,Serial No. 131,709

This invention-.relatestoimprovements in feeler tips for weft detectors anditis the general object .of theinventionlto provide a tip .having a surface which shall be hard and possessed of very .low

oxidizing qualities so that-itcanbe usedfor electricaLfeelers.

Electrical weft detectors as made .at present employ a pair of oppositelycharged electrodes to be-e'lectrically connected by..a.meta1lic..ferrule .on

a'bobbin when vthe'we'fto'f the latter is depleted. The lowest permissible voltages cause sparking which leaves-a fineblack deposit on the feeler tips. The weft carrier which comes into action as a result of feeler indication strikes the blackened tip surface with resultant darkening of the weft which shows in the finished cloth.

It is an important object of my present invention to employ a feeler tip which is sufliciently hard to withstand repeated contacts with hard wound Weft and at the same time is practically non-oxidizable so that should a spark occur at the time of indicating weft exhaustion there will be little or no deposit on the detector tip and the freshly inserted supply of weft will not be marked as heretofore.

i The metal which I prefer to use is an alloy of palladium and iridium. Both of these metals are practically non-oxidizable at ordinary temperatures and I employ the iridium principally for the purpose of producing an alloy that will be harder and more resistant to wear than pure palladium.

These metals are relatively expensive and it is a further object of my invention to provide an improved means for holding a small amount of such metal to an electrically conducting head and held in such a way that the latter cannot have contact with the ferrule on the bobbin being detected. This result I may accomplish by having the detector surface spherical or convex and attached to the head so that no exposed part of it can contact with the ferrule. The head may be made of brass which is easily oxidizable and would discolor the weft if permitted to contact directly with the ferrule.

With these and other objects in view which will appear as the description proceeds, my invention resides in the combination and arrangement of parts hereinafter described and set forth in the claims.

In the accompanying drawing, wherein two diiferent forms of feeler tip are shown,

Fig. 1 represents a detector and bobbin of the electrical type with my invention applied thereto, Fig. 2 is a vertical section on line 22 of Fig. 1,

.Fig. 3 .is an enlarged vertical section on line 33 of Fig. ,1,

Fig. 4 is 'a view similar to Fig. 3 but with a slightly different method of holding "the tip in invention.

Referringto Fig. 1,'the bobbintB-mayibe of the usual type -.andahas-.a smetallicrferrule F .of: electric m conducting material.

The weft W normallycovers .this ferrule .but .as .depletion approaches .the ferrule is uncovered and there will remain a reserve bunch as indicated in Fig. 1. Under these conditions electrodes I0 and II of the detector D 15 will be electrically connected so that a current can flow through wires I2 and I3 which are connected, respectively, to the detector electrodes Ill and II. When current flows through these wires a change will be brought about in the op- 20 eration of the loom, such as bobbin or shuttle replacement, or loom stoppage. The feeler body I4 is made of insulating material and has a pair of channels l5 housing springs l6 which urge the electrodes rearwardly or toward the bobbin but 25 permit forward yielding movement of the electrodes when the bobbin is advanced by the lay on the detecting beat of the loom.

So far as my present invention is concerned it is immaterial what particular result is caused by 30 current flowing through the wires l2 and [3. For a more complete description of the structure and operation of the principal part of the detector reference may be had to my prior Patent No. 1,924,197. 35

In carrying my invention into effect I provide an improved form of tip for the electrodes Ill and II. The preferred form shown in Fig. 3 may be formed of a piece of metallic wire having the rear end threaded as at 2!] to which is threaded a head 40 2| of some current conducting material, such as brass. The rear part of the head may have a convex surface 22 which is preferably spherical and there is applied to this head a small sheet 23 of an alloy made substantially of palladium and 15% iridium. This plate, which may be dished for the purpose, fits the contour of the convex surface 22 and may be soldered thereto, if desired. The rear surface 24 may be polished to 50 render the same smooth.

In the modified form of tip as shown in Fig. 4 a current conducting head 30 is secured to the current conducting wire electrode 3| and has a tapped bore 32 to receive a threaded end of wire 5 3|. Prior to application of the detecting surface the head may be formed as shown in Fig. 5 with a rearwardly facing convex preferably spherical surface 33 around which extends a rim 34 turned to a thin edge. A shell 35 substantially similar to the shell 23 is then placed on the surface 33 and the rim 34 is turned down as at 36 to hold the shell in place. The shell may be made of the same material as the shell 23 but instead of being soldered in place it in held in place by the turned down edges of the rim 34. e I

In both forms of the invention it will be seen that the rear surface of the rounded shell extends behind all parts of the head so that the latter has no opportunity to contact with the ferrule. The result is that the electric current which flows at the time indication of weft exhaustion is given is required to pass entirely through the palladium iridium alloy. Because of the nature of this alloy it does not burn in such a Way as to form a black powder and any sparking which results from indication of weft exhaustion leaves these surfaces practically clean, so that the bobbin which is put into action after indication is not subjected to the repeated blows of a blackened electrode.

While I have given specific proportions for the metals which form the alloy, yet I do not wish to be limited strictly to the figures given. I have found that platinum operates satisfactorily and so far as certain features of my invention are concerned I do not wish to be limited to the particular metal or alloy which is held by the head 2| or 30.

From the foregoing it will be seen that I have provided a simple form of feeler tip which operates to close a circuit at the time of weft exhaustion without being burned. This is due to the fact that the feeler tip is formed of material having very low oxidizing tendencies and that the detecting surface formed of this material lies behind the head of less suitable material to which the detecting surface is secured.

Having thus described my invention it will be seen that changes and modifications may be made therein by those skilled in the art without departing from the spirit and scope of the invention and I do not wish to be limited to the details herein disclosed, but what I claim is:

1. An electric feeler tip having a head of readily oxidizable metal formed with a convex rear surface, and a disk of a palladium and iridium alloy fitted to the convex surface and projecting beyond the rear part of the head, the head having portions to extend behind the disk to hold the latter in place on the head.

2. In an electric feeler tip, a supporting wire, a head of readily oxidizable metal threaded onto the wire and having a convex rear surface, a disk of a metal having a low oxidizing tendency conformed to the convex surface and protruding behind the rearmost part of the head and held to said head.

OSCAR V. PAYNE. 

